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  1. Article ; Online: Covalent Si–H Bonds in the Zintl Phase Hydride CaSiH 1+ x ( x ≤ 1/3)

    Henry Auer / Fangshun Yang / Helen Y. Playford / Thomas C. Hansen / Alexandra Franz / Holger Kohlmann

    Inorganics, Vol 7, Iss 9, p

    2019  Volume 106

    Abstract: The crystal structure of the Zintl phase hydride CaSiH ≈4/3 was discussed controversially, especially with respect to the nature of the silicon-hydrogen interaction. We have applied X-ray and neutron powder diffraction as well as total neutron scattering ...

    Abstract The crystal structure of the Zintl phase hydride CaSiH ≈4/3 was discussed controversially, especially with respect to the nature of the silicon-hydrogen interaction. We have applied X-ray and neutron powder diffraction as well as total neutron scattering on a deuterated sample, CaSiD 1.1 . Rietveld refinement (CaSiD 1.1 , Pnma , a = 14.579(4) Å, b = 3.8119(4) Å, c = 11.209(2) Å) and an analysis of the neutron pair distribution function show a silicon-deuterium bond length of 1.53 Å. The Si−H bond may thus be categorized as covalent and the main structural features described by a limiting ionic formula Ca 2+ H − (Si − ) 2/3 (SiH − ) 1/3 . Hydrogen atoms decorating the ribbon-like silicon polyanion made of three connected zigzag chains are under-occupied, resulting in a composition CaSiH 1.1 . Hydrogen-poor Zintl phase hydrides CaSiH <1 with hydride ions in Ca 4 tetrahedra only were found in an in situ neutron diffraction experiment at elevated temperature. Hydrogen (deuterium) uptake and release in CaSiD x (0.05 ≤ x ≤ 0.17) is a very fast process and takes less than 1 min to complete, which is of importance for possible hydrogen storage applications.
    Keywords Zintl phase ; Zintl phase hydride ; metal hydride ; neutron diffraction ; Rietveld refinement ; pair distribution function ; polyanions ; hydrogen storage ; silicon ; in situ ; Inorganic chemistry ; QD146-197
    Subject code 290
    Language English
    Publishing date 2019-08-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Li1.5La1.5 MO6 (M = W6+, Te6+) as a new series of lithium-rich double perovskites for all-solid-state lithium-ion batteries

    Marco Amores / Hany El-Shinawi / Innes McClelland / Stephen R. Yeandel / Peter J. Baker / Ronald I. Smith / Helen Y. Playford / Pooja Goddard / Serena A. Corr / Edmund J. Cussen

    Nature Communications, Vol 11, Iss 1, Pp 1-

    2020  Volume 12

    Abstract: The development of the all solid-state battery requires the formation of stable solid/solid interfaces between different battery components. Here the authors tailor the composition to form both electrolyte and anode from the same novel family of ... ...

    Abstract The development of the all solid-state battery requires the formation of stable solid/solid interfaces between different battery components. Here the authors tailor the composition to form both electrolyte and anode from the same novel family of perovskites with shared crystal chemistry.
    Keywords Science ; Q
    Language English
    Publishing date 2020-12-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Spin-ice physics in cadmium cyanide

    Chloe S. Coates / Mia Baise / Adrian Schmutzler / Arkadiy Simonov / Joshua W. Makepeace / Andrew G. Seel / Ronald I. Smith / Helen Y. Playford / David A. Keen / Renée Siegel / Jürgen Senker / Ben Slater / Andrew L. Goodwin

    Nature Communications, Vol 12, Iss 1, Pp 1-

    2021  Volume 8

    Abstract: Spin-ice physics in frustrated magnets is constrained by the energy scale of magnetic interactions, which typically translates to temperatures of a few Kelvin. Here, the authors demonstrate that similar physics can be observed in the system of frustrated ...

    Abstract Spin-ice physics in frustrated magnets is constrained by the energy scale of magnetic interactions, which typically translates to temperatures of a few Kelvin. Here, the authors demonstrate that similar physics can be observed in the system of frustrated electric dipoles in Cd(CN)2 even at room temperature.
    Keywords Science ; Q
    Language English
    Publishing date 2021-04-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article: Pair Distribution Function Analysis of Structural Disorder by Nb5+ Inclusion in Ceria: Evidence for Enhanced Oxygen Storage Capacity from Under-Coordinated Oxide

    Hiley, Craig I / David Thompsett / Helen Y. Playford / Janet M. Fisher / Noelia Cortes Felix / Reza J. Kashtiban / Richard I. Walton

    Journal of the American Chemical Society. 2018 Feb. 07, v. 140, no. 5

    2018  

    Abstract: Partial substitution of Ce4+ by Nb5+ is possible in CeO2 by coinclusion of Na+ to balance the charge, via hydrothermal synthesis in sodium hydroxide solution. Pair distribution function analysis using reverse Monte Carlo refinement reveals that the small ...

    Abstract Partial substitution of Ce4+ by Nb5+ is possible in CeO2 by coinclusion of Na+ to balance the charge, via hydrothermal synthesis in sodium hydroxide solution. Pair distribution function analysis using reverse Monte Carlo refinement reveals that the small pentavalent substituent resides in irregular coordination positions in an average fluorite lattice, displaced away from the ideal cubic coordination toward four oxygens. This results in under-coordinated oxygen, which explains significantly enhanced oxygen storage capacity of the materials of relevance to redox catalysis used in energy and environmental applications.
    Keywords catalytic activity ; ceric oxide ; cerium ; energy ; oxygen ; sodium ; sodium hydroxide
    Language English
    Dates of publication 2018-0207
    Size p. 1588-1591.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.7b12421
    Database NAL-Catalogue (AGRICOLA)

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  5. Article ; Online: ζ-Glycine

    Craig L. Bull / Giles Flowitt-Hill / Stefano de Gironcoli / Emine Küçükbenli / Simon Parsons / Cong Huy Pham / Helen Y. Playford / Matthew G. Tucker

    IUCrJ, Vol 4, Iss 5, Pp 569-

    insight into the mechanism of a polymorphic phase transition

    2017  Volume 574

    Abstract: Glycine is the simplest and most polymorphic amino acid, with five phases having been structurally characterized at atmospheric or high pressure. A sixth form, the elusive ζ phase, was discovered over a decade ago as a short-lived intermediate which ... ...

    Abstract Glycine is the simplest and most polymorphic amino acid, with five phases having been structurally characterized at atmospheric or high pressure. A sixth form, the elusive ζ phase, was discovered over a decade ago as a short-lived intermediate which formed as the high-pressure ∊ phase transformed to the γ form on decompression. However, its structure has remained unsolved. We now report the structure of the ζ phase, which was trapped at 100 K enabling neutron powder diffraction data to be obtained. The structure was solved using the results of a crystal structure prediction procedure based on fully ab initio energy calculations combined with a genetic algorithm for searching phase space. We show that the fate of ζ-glycine depends on its thermal history: although at room temperature it transforms back to the γ phase, warming the sample from 100 K to room temperature yielded β-glycine, the least stable of the known ambient-pressure polymorphs.
    Keywords amino acids ; crystal structure prediction ; polymorphism ; neutron diffraction ; phase transitions ; crystallization under non-ambient conditions ; Science ; Q
    Language English
    Publishing date 2017-09-01T00:00:00Z
    Publisher International Union of Crystallography
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article: Structure–property insights into nanostructured electrodes for Li-ion batteries from local structural and diffusional probes

    Laveda, Josefa Vidal / Beth Johnston / Gary W. Paterson / Peter J. Baker / Matthew G. Tucker / Helen Y. Playford / Kirsten M. Ø. Jensen / Simon J. L. Billinge / Serena A. Corr

    Journal of materials chemistry. 2017 Dec. 19, v. 6, no. 1

    2017  

    Abstract: Microwave heating presents a faster, lower energy synthetic methodology for the realization of functional materials. Here, we demonstrate for the first time that employing this method also leads to a decrease in the occurrence of defects in olivine ... ...

    Abstract Microwave heating presents a faster, lower energy synthetic methodology for the realization of functional materials. Here, we demonstrate for the first time that employing this method also leads to a decrease in the occurrence of defects in olivine structured LiFe₁₋ₓMnₓPO₄. For example, the presence of antisite defects in this structure precludes Li⁺ diffusion along the b-axis leading to a significant decrease in reversible capacities. Total scattering measurements, in combination with Li⁺ diffusion studies using muon spin relaxation (μ⁺SR) spectroscopy, reveal that this synthetic method generates fewer defects in the nanostructures compared to traditional solvothermal routes. Our interest in developing these routes to mixed-metal phosphate LiFe₁₋ₓMnₓPO₄ olivines is due to the higher Mn²⁺/³⁺ redox potential in comparison to the Fe²⁺/³⁺ pair. Here, single-phase LiFe₁₋ₓMnₓPO₄ (x = 0, 0.25, 0.5, 0.75 and 1) olivines have been prepared following a microwave-assisted approach which allows for up to 4 times faster reaction times compared to traditional solvothermal methods. Interestingly, the resulting particle morphology is dependent on the Mn content. We also examine their electrochemical performance as active electrodes in Li-ion batteries. These results present microwave routes as highly attractive for reproducible, gram-scale syntheses of high quality nanostructured electrodes which display close to theoretical capacity for the full iron phase.
    Keywords electrochemistry ; electrodes ; energy ; iron ; lithium ; lithium batteries ; manganese ; microwave treatment ; nanomaterials ; olivine ; phosphates ; redox potential ; spectroscopy
    Language English
    Dates of publication 2017-1219
    Size p. 127-137.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 2702232-8
    ISSN 2050-7496 ; 2050-7488
    ISSN (online) 2050-7496
    ISSN 2050-7488
    DOI 10.1039/c7ta04400c
    Database NAL-Catalogue (AGRICOLA)

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